1. Field of the Invention
The present invention relates to a method of constructing the top slab of a steel-reinforced concrete nuclear reactor container in a nuclear power generating plant and also to a nuclear reactor container constructed by such a method.
2. Description of the Related Art
A known construction method will be described with reference to FIG. 5 which shows the construction of a nuclear reactor container made of steel-reinforced concrete, FIG. 6 which is an illustration of a top slab portion of the nuclear reactor container, illustrative of the conventional construction method and FIG. 7 which is a flow chart of the known construction method.
The nuclear reactor container made of steel-reinforced concrete has a bottom-equipped cylindrical portion 2, a top slab 4 and a top head 5. The interior of the container is divided into two spaces by a diaphragm floor 3. The nuclear reactor container contains a pressure vessel 6 of a nuclear reactor and forms a portion of a nuclear reactor house 1.
The known construction method will be described with specific reference to FIGS. 6 and 7. After mounting a liner 11 for the cylindrical portion, temporary posts 14 and temporary trusses 15 are installed and a top slab liner 10 is placed on the top of the temporary trusses 15. A flanged sleeve 7 of the nuclear reactor container is set up and welding is conducted at the welding lines 12 and 13. Then, doughnut-shaped top slab reinforcers 8 are assembled on the top slab liner 10. Subsequently, the reinforcers 9 for the cylindrical portion are set up and connected to the top slab reinforcers 8. Then, a concrete is poured and, after drying and solidification of the concrete, the temporary posts 14 and the temporary trusses 15 are removed.
Arts pertaining to this known construction method are: a method of constructing a cylindrical liner (Japanese Patent Laid-Open No. 62-170885), a method in which beams are extended through a steel-reinforced concrete top slab forming the upper structure of a nuclear reactor core, the beams being connected to a lining (Japanese Patent Laid-Open No. 62-165185), a non-unitizing top slab installation method (Japanese Patent Laid-Open No. 62-169082), an art relating to liner structure of cylindrical a portion of a reactor container (Japanese Patent Laid-Open No. 62- 298794), and a method of laying steel reinforcers (Japanese Patent Laid-Open No. 64-74498).
The following arts are also proposed: a hollow pre-cast slab incorporating steel reinforcement beams and a method of producing the same (Japanese Patent Laid-Open No. 49-111420), a method of constructing a floor using a deck plate in place of a frame (Japanese Patent Laid-Open No. 52-26714), a method of constructing an intermediate slab of a base structure of nuclear 2 reactor for supporting a nuclear reactor pressure vessel (Japanese Patent Laid-Open No. 56-125691), a method in which an H-shaped steel is attached to each side of a lining for a concrete container (Japanese Patent Laid-Open No. 57-19696), a method in which works such as attaching of trays with ceilings, ducts, pipes and supporting structures are to deck beams and set-up of pipes to upper side of beams are conducted in a factory thus unitizing ceiling deck plate (Japanese Patent Laid-Open No. 57-57289), a method of lining the side wall of a reactor container made of steel-reinforced concrete, wherein the liner is integrated with steel reinforcers (Japanese Patent Laid-Open No. 59-142496), a method in which pipes to be buried in the floor of a reactor house are assembled in steel reinforcer units (Japanese Patent Laid-Open No. 62-273347), and a method in which steel reinforcers of a cylindrical portion of a shield wall is assembled from a plurality of units (Japanese Patent Laid-Open No. 64-79693).
In these known arts, however, no consideration has been given to the efficiency in constructing a nuclear reactor container having a sleeve with a flange of an outside diameter which is greater than the inside diameter of a doughnut-shaped steel-reinforced structure. This problem has caused an impediment in constructing a nuclear reactor container.